Migrate old Trac wiki pages to GitHub wiki pages

[clange]

The old Trac wiki pages, currently archived at http://www.iai.uni-bonn.de/~langec/exchange/krextor/, should be migrated to GitHub wiki pages.

(@fzdabc, @shinhokang, @elisasibarani, @IGG777: note the new location, where the files are easier to access.)

@elisasibarani in case you are wondering about me creating this issue: I'm currently writing a placeholder README file from which I'm pointing to this issue to make our further planned steps transparent to visitors.

[elisasibarani]

Sure, no problem Christoph @clange. I am currently working on that and will let you know the progress or in case if I have a question.

[clange]

Many thanks @elisasibarani for the initial migration of the documentation. I have meanwhile made the former "Index" page the new homepage of the wiki, and updated some information there. Now, could you please make a few checks and fixes to the other pages?

• On those pages that I archived from The Web Archive, links to external websites (e.g. in https://github.com/EIS-Bonn/krextor/wiki/Acknowledgments) point to archived pages rather than the actual pages.
• Many pages, e.g. https://github.com/EIS-Bonn/krextor/wiki/Documentation, link to source files of Krextor. Could you please follow the instructions at http://stackoverflow.com/a/7658676 to make them point to the source files in this repository?